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1.
Body distribution and growth- and nutritional status-dependent accumulation of 21 trace elements were investigated in harbor seals (Phoca vitulina) stranded in the North Sea coast in 2002. Higher concentrations and burdens of Mn, Se, Mo, Ag, Sn, Hg, and Bi in the liver, Cd in the kidney, As in the blubber, and Co, Sr, and Ba in the bone were observed. Significant positive correlations of hepatic Se, Mo, Ag, Cd, Sn, Hg, Tl, and Bi with standard body length were found, while significant negative relationships were detected for Mn, As, Rb, Sr, and Sb in the liver. Concentrations of Co, Se, Sr, Sn, Hg, and Bi in the liver, V, Sr, Ag, Sn, and Hg in the kidney, V, Mn, Co, Rb, Sr, Sn, Ba, and Pb in the blubber increased with decreasing blubber thickness of harbor seals, indicating enrichment of these elements in the target tissue by emaciation.  相似文献   

2.
Improving our ability to detect changes in terrestrial and aquatic systems is a grand challenge in the environmental sciences. In a world experiencing increasingly rapid rates of climate change and ecosystem transformation, our ability to understand and predict how, when, where, and why changes occur is essential for adapting and mitigating human behaviours. In this context, long-term field research infrastructures have a fundamentally important role to play. For northern boreal landscapes, the Krycklan Catchment Study (KCS) has supported monitoring and research aimed at revealing these changes since it was initiated in 1980. Early studies focused on forest regeneration and microclimatic conditions, nutrient balances and forest hydrology, which included monitoring climate variables, water balance components, and stream water chemistry. The research infrastructure has expanded over the years to encompass a 6790 ha catchment, which currently includes 11 gauged streams, ca. 1000 soil lysimeters, 150 groundwater wells, >500 permanent forest inventory plots, and a 150 m tall tower (a combined ecosystem-atmosphere station of the ICOS, Integrated Carbon Observation System) for measurements of atmospheric gas concentrations and biosphere-atmosphere exchanges of carbon, water, and energy. In addition, the KCS has also been the focus of numerous high resolution multi-spectral LiDAR measurements and large scale experiments. This large collection of equipment and data generation supports a range of disciplinary studies, but more importantly fosters multi-, trans-, and interdisciplinary research opportunities. The KCS attracts a broad collection of scientists, including biogeochemists, ecologists, foresters, geologists, hydrologists, limnologists, soil scientists, and social scientists, all of whom bring their knowledge and experience to the site. The combination of long-term monitoring, shorter-term research projects, and large-scale experiments, including manipulations of climate and various forest management practices, has contributed much to our understanding of boreal landscape functioning, while also supporting the development of models and guidelines for research, policy, and management.  相似文献   

3.
We determined the partition coefficients of 19 elements between metallic liquid and silicate liquid at 20 GPa and 2500°C, and between metallic liquid and silicate perovskite at 27 GPa and 2200°C. Remarkable differences were observed in the partitioning behaviors of Si, P, W, Re, and Pb among the silicate liquid, perovskite, and magnesiowüstite coexisting with metallic liquid, reflecting incompatibility of the elements in the silicate or oxide phase. We could not observe any significant difference in the partitioning behaviors of V, Cr, Mn, Co, Ni, and Cu among the phases coexisting with metallic liquid.

Comparison of the present partitioning data with those obtained previously at lower pressure and temperature suggests that the exchange partition coefficients, Kmet/sil, of Co, Ni, Mo, and W decrease, whereas those of V, Cr, and Mn increase and tend to approach unity with increasing pressure and temperature. We also made preliminary experiments to clarify the effect of sulfur on the partitioning behaviors. Sulfur lowers the exchange partition coefficients, Kmet/sil, of Mo and W between metallic liquid and silicate liquid significantly at 20 GPa and 2300°C.

The mantle abundances of Co, Ni, Cu, Mo, and W calculated for the metal-silicate equilibrium model are lower than those of the real mantle, whereas P, K, and Mn are overabundant in the calculated mantle. The discrepancies in the abundances of Co and Ni could be explained by the chemical equilibrium at higher pressure and temperature. Large discrepancies in Mo and W between the calculated and real mantles could be accounted for by the effect of sulfur combined with the effects of pressure and temperature on the chemical equilibrium. The mantle abundances of P, K, and Cu could be accounted for by volatile loss in the nebula, perhaps before accretion of the Earth, combined with the chemical equilibrium at higher pressure and temperature. Thus the observed mantle abundances of P, K, Co, Ni, Cu, Mo, and W may be consistent with a model of sulfur-bearing metal-silicate equilibrium in lower-mantle conditions.  相似文献   


4.
李传琼  王鹏  陈波  李燕 《湖泊科学》2018,30(1):139-149
于2015年1月和7月在赣江干流和主要支流37个采样点共采集74个水样,分析赣江水系15种溶解态金属元素(Be、Al、V、Mn、Fe、Co、Ni、Cu、As、Mo、Cd、Sb、Tl、Pb、U)的空间分布特征和污染来源的贡献率.结果表明:多数水样的溶解态金属元素浓度符合水质标准,主要的超标元素是Fe,样品超标率为21.60%,其次为As(8.10%)、Mn(4.05%)、Tl(4.05%)和Al(1.35%).Be、Al、V、Fe、Co、Ni、Cu、U浓度在枯水期显著高于丰水期,其他元素差异不显著.依据溶解态金属元素的空间分布特征,赣江流域可分为3个区域:湘水、章水和赣江赣州市段(C1),桃江、袁水和锦江(C2),其他区域(C3);溶解态金属元素水平大小排序为C1C2C3,其中Be、Al、Cu、Mo、Sb、As浓度在C1最高,V、Mn、Fe、Ni、Cd浓度在C2最高.采矿废水、矿渣和农田土壤降雨淋滤、钢铁冶炼废水是赣江溶解金属元素的主要来源;Be、Al、Cu、Pb、U的污染源超过40%来自采矿废水,Cu、As、Mo、Cd的污染源超过35%来自矿渣和农田土壤降雨淋滤,V、Mn、Co、Ni的污染源超过41%来自钢铁冶炼废水.  相似文献   

5.
为识别表层沉积物重金属的来源以及量化源贡献,选取鄱阳湖丰水期表层沉积物为研究对象,测定14种重金属(V、Cr、Co、Ni、Cu、Zn、Sr、Mo、Cd、Sb、W、Pb、Hg和As)的含量,分析其污染及空间分布特征,并利用主成分分析法(PCA)和正定矩阵因子分解法(PMF)对沉积物重金属进行源解析.结果表明:除V和Cr外,Cd、Mo、Hg、Cu、Pb、Zn、W、Sr、As、Ni、Co和Sb的平均含量分别为江西省土壤背景值的5.7、2.2、1.9、1.8、1.5、1.5、1.4、1.3、1.3、1.2、1.0和1.0倍; Cd、Hg、Cu、Mo、Pb、Sr和Zn超出江西省土壤背景值的比例相对较高,分别为100%、100%、100%、100%、97%、97%和93%,所有沉积物样品中Cd含量超过农用地土壤污染风险筛选值的比例为51%; V、Cr、Co、Ni、Cu、Zn、Sr、Mo、Sb、W、Pb、Hg和As含量呈未污染至弱污染水平,而Cd含量属于中等污染水平,接近于重污染水平.总体而言,Cd的污染相对较严重.重金属的分布具有显著的区域特征,其中Cr、Cu、Zn、Sr、Pb、Hg和As的空间分布十分相似,表现为在赣江、抚河、信江和饶河入湖口附近区域含量较高,而Co、Ni、Mo和Sb明显在湖区南部、东北部和修水入湖附近这3个区域聚集,Cd和W的空间变异性相对较大,V的含量分布相对较均匀.PCA和PMF解析结果都表明鄱阳湖丰水期表层沉积物重金属受4种来源的共同影响,其中,矿业和工业活动的影响最大,相对贡献率为38%,其次是尾矿和废渣,相对贡献率为28%,再是农业活动,相对贡献率为19%,最后是自然来源的相对贡献率为14%.  相似文献   

6.
In the present work, histological changes in the gill, liver, kidney and intestine of Notopterus notopterus, induced by pulp waste, paper waste and mixed pulp and paper waste, have been studied both at sublethal and lethal concentrations. The pulp waste produces much more histological changes both at sublethal and lethal concentrations in the gill, liver, kidney and intestine as compared to paper waste and mixed pulp and paper waste. The changes are much more remarkable in the case of sublethal concentration, as compared to a lethal concentration. In a sublethal concentration, the localized necrosis, atrophy and partial and total liquefaction of epithelial cells, pilaster cells, mucous cells of the gill, hepatic cells of the liver, mesenchymatous cells, renal tubule cells and Bowman's capsule of the kidney, mucosal and submucosal cells and blood vessels of intestine have been observed. In lethal concentration, the changes are much more marked in the gill, as compared to the liver, kidney and intestine. The histological changes, produced in the different types of cells and in the tissue as a whole, can be correlated with the different chemical components present in the pulp waste, paper waste and mixed pulp and paper waste.  相似文献   

7.
稻田氮磷径流流失模型研究进展   总被引:1,自引:0,他引:1  
黄微尘  周丰  梁浩  陈磊 《湖泊科学》2021,33(2):336-348
水稻是全球最重要的粮食作物,但种植过程中不合理的水肥管理引起了稻田氮磷径流流失,对邻近水体造成污染风险.稻田氮磷径流流失模型是理解区域水体污染排放时空特征和评估水污染风险的有效手段.论文阐述了稻田氮磷径流流失的发生机制和关键过程,梳理了统计经验模型、物理机理模型、水文过程模型和生态系统模型的研发历程.结果表明,当前模型缺乏水—土—气界面过程的有效参数化,基于高分辨率、多年多站点、全通量的模型参数的合理化,以及区域尺度农艺管理(种植制度、施肥制度、灌排制度)和田—沟—塘联合调控措施(分布、规模、运行规则)的模块化,造成了稻田氮磷径流流失的不确定性.同时,提出了面向稻田氮磷循环的高分辨率全通量观测网络建设、农艺管理与调控措施的区域数据集研发、模型开发与先进技术手段的集成与融合、稻田—氮—磷—水耦合的多模型集合等,为稻田氮磷径流流失模型的改进、农艺管理措施的优化以及气候智能型稻田的建设提供科学依据.  相似文献   

8.
目的:评价CTA在诊断及治疗颅内动脉瘤中的临床应用价值。方法:97例临床疑似颅内动脉瘤患者中首先随机选择CTA及MRA两种无创伤检查中的一种,随后均行DSA检查。以DSA和外科手术确诊为参考,比较CTA,MRA及DSA在诊断颅内动脉瘤中的优势和不足。选择相应治疗后,行CTA+DSA或MRA+DSA复查,评价动脉瘤的残留情况。结果:①50例行CTA+DSA检查组中,确诊阳性病例46例。CTA检测的特异性、灵敏性及准确性分别为66.67%、100%和98%。阴性及阳性预测率分别为100%和97.92%。DSA检测的特异性、灵敏性及准确性分别为66.67%、95.74%和94%。阴性及阳性预测率分别为50%和97.83%。②47例行MRA+DSA检查组中,确诊阳性病例45例。MRA检测的特异性、灵敏性及准确性分别为50%、97.67%和93.62%。阴性及阳性预测率分别为66.67%和95.45%。DSA检测的特异性、灵敏性及准确性分别为66.67%、97.73%和95.74%。阴性及阳性预测率分别为66.67%和97.73%。③48例接受动脉瘤颈夹闭术的患者行CTA+DSA复查,以DSA为标准,CTA评价动脉瘤残留的特异性、灵敏性及准确性分别为97.73%、100%和97.78%。42例接受可解脱弹簧圈治疗的患者行MRA+DSA复查,以DSA为标准,MRA评价动脉瘤残留的特异性、灵敏性及准确性分别为100%、66.67%和97.5%。结论:CTA诊断颅内动脉瘤的特异性、灵敏性及准确性稍优于DSA,MRA对于颅内动脉瘤的诊断方面稍低于DSA;同时CTA及MRA均可清晰显示动脉瘤的三维结构及空间关系;综合比较,我们认为CTA对于动脉瘤的诊断及手术方案的确定能提供更多的信息,并可作为术后较为理想的随访影像学检查方法。   相似文献   

9.
大型超大型金属矿床综合信息成矿预测方法研究   总被引:22,自引:12,他引:10  
大型超大型矿床在其时空分布、控矿因素、形成机制、成矿模式诸方面与一般中小型矿床有相似甚至雷同之处,也有其特殊、独特方面,研究预测大型超大型矿床相当复杂,需要从不同学科、不同侧面、不同角度、不同途径、不同方法及不同思路进行综合研究。本文给出大型超大型矿床预测的综合信息方法,认为地质地球物理地球化学多学科综合分析是今后找矿的最主要途径。通过对大型、超大型矿床的趋群性特点分析,给出了矿床密集区的概念以及圈定的基本原则和边界条件。通过对大型超大型矿床发现途径的分析,指出大型超大型矿床的分布具有可预测性。并表述了综合信息预测方法流程,以矿床密集区为模型单元,以异常密集区为预测单元,通过地质、地球物理、地球化学等综合信息控矿地质变量的提取和合理赋值,加上数理统计方法的合理应用,达到对大型超大型矿床的预测目的。  相似文献   

10.
Five sediment zones(20 samples) were collected in Mighan Lake,near Arak city in Markazi province,and were analyzed to reveal element sources and assess the quality of metal contamination.Both anthropogenic and natural origins were identified by correlation,factor,and cluster analyse.According to the enrichment factors(EF) of trace metals(Ba,Co,Cr,Cu,Ni,Pb,Rb,Sr,Zr,and Zn),three groups were identified.Enriched trace elements included:Ni,Zn,and Sr.Comparisons with contamination degree and benchmark sediment quality criteria and guidelines showed that Mighan Lake has potential for adverse effects on aquatic biota because of Ni,Zn,and Cr.  相似文献   

11.
Results of mercury and organochlorine analyses in pooled muscle and blubber samples representing in all 417 long-finned pilot whales (Globicephala melas) sampled in 1997 in the Faroe Islands are presented. The 28 pooled muscle samples from (in all) 9 pods were analysed for total mercury and the same number of pooled blubber samples were analysed for PCB (IUPAC CBs no. 28, 52, 99, 101, 105, 118, 128, 138, 153, 170, 180, 183 and 187), p,p′-DDT and metabolites and o,p′-DDT and metabolites, cis () and trans (γ)-chlordane, cis- and trans-nonachlor, oxychlordane, mirex, hexachlorobenzene, β-HCH and toxaphene (Parlars no. 26 (T2), 32, 50 (T12), 62 (T20) and 69.  相似文献   

12.
目的:根据多排螺旋CT肺部亚实性结节(SSN)三维重建的定量参数、血液肿瘤标志物和血常规指标,建立用于判断有浸润倾向肺腺癌的多参数诊断模型。材料与方法:回顾性纳入107例接受薄层CT扫描,术后行组织学检查,并做了血液肿瘤标志物和血常规检查的患者。评估指标包括患者年龄、性别;SSN在CT三维重建中的最大径、总体积、实性成分占比和平均CT值;以及血液实验室指标:CEA、CYFRA21-1、NSE、CA125、CA153、CA242、CA199、CA724、SCC、CRP、WBC、NEUT和NEUT%。建立多元logistic回归模型,采用受试者工作特征曲线下面积(AUC)评价该模型对有浸润倾向SSN的诊断能力。结果:在良性和浸润前病变组(51例),以及微浸润腺癌和浸润性腺癌组(56例)之间,年龄、SSN最大径、总体积、实性成分占比和平均CT值有显著差异(P<0.05)。上述参数建立的多元回归模型中,SSN最大径(P=0.007)和实性成分占比(P=0.004)具有显著性。SSN最大径、实性成分占比和多元模型预测有浸润倾向SSN的AUC分别为0.764、0.749和0.801。结论:在体检可以获得的CT定量和一些血液肿瘤标志物和血常规参数中,使用SSN最大径和实性成分占比建立综合诊断模型,能有效预测SSN的浸润性,有助于在肺癌筛查中发现需要手术的患者。   相似文献   

13.
中国多年来在岩石圈物理学研究中已取得了一系列的重要成果,并促进了中国地球科学的发展。然而在这21世纪之际,基于国家战略需求和自主创新的方针对岩石圈物理学提出了新的挑战。本文在这样的思维前提下对岩石圈物理学的科学内涵和发展导向进行了较全面的分析、研究和思考,并明确指出当今在这一学科领域应该做些什么,核心问题是什么,又存在哪些关键性的科学问题。研究结果提出,高精度的地球物理场观测与岩石圈内壳、幔精细结构(2维和3维)的刻划;在地球内部力系作用下,深部物质和能量的交换;深部物质运移的物理-力学-化学作用过程及深层动力学响应乃是深化对地球本体的认识和揭示成山、成盆、成岩、成矿和成灾的根本机理所在。为此,在本世纪的上、中叶,在地球科学领域中地球物理学研究必为先导。本文最后对岩石圈物理研究中尚存在的一些问题和困惑进行了分析和讨论。  相似文献   

14.
China has achieved much during recent years in the area of lithospheric physics research and promoted the development of the geosciences (Teng, 2004). However, in the 21^st century, national needs and policy challenges the science of lithospheric physics. I suggest a general analysis, research, and development direction for lithospheric physics and point out clearly the content, core problems, and key scientific problems in this field. The realization of the earth and the discovery of the basic mechanisms of mountains, basins, minerals, and natural disasters depend basically on high-resolution observations of geophysics, the delineation of the fine structure of crust and mantle (2D and 3D) inside the lithosphere, substance and energy exchanges in the deep earth, the process of deep physical, mechanical, and chemical actions, and deep dynamical response. Therefore, geophysics should be the pioneer in the geosciences field in the first half of the 21^st century. I end with an analysis and discussion of some problems and difficulties in the research of lithospheric physics.  相似文献   

15.
Concentrations of Cd, Cr, Cu, Ni and Pb were determined in filtered water, suspended particulate matter, and bottom sediments from a 2000 km section of the Ob and Irtysh Rivers. Dissolved Cd, Cr, Cu and Ni concentrations are similar to, or higher than, results from other Russian Arctic and large world river-estuaries. Concentrations of Cd, Cr, Cu, Ni and Pb in suspended particulate matter are generally comparable to results from other Russian Arctic and large world rivers and estuaries. Comparison of trace metal ratios in crustal material and suspended particulate matter and bottom sediment suggests that the source of Cr, Cu and Ni is continental weathering. Particulate Cd and Pb are elevated relative to their crustal abundance, suggesting a source of these metals to the Ob-Irtysh in addition to continental weathering.  相似文献   

16.
肯吉亚克油田石炭系油藏属持低孔渗、异常高压碳酸盐岩油藏,它除了具有埋深大,非均质性强,油气成藏控制因素复杂等特点外,其上还覆盖巨厚盐丘,造成盐下地震反射时间和振幅畸变严重,地震成像差、信噪比低和分辨率低,给储层预测工作带来极大困难。如何正确预测油藏高产带分布规律是高效开发这类油藏的关键,本文研究从分析形成碳酸盐岩油藏高产带的主控因素入手,通过井震标定,优选反映碳酸盐岩岩相、岩溶、物性和裂缝的地震属性,结合地震、地质、测井、油藏工程和钻井资料,把盐下特低孔渗碳酸盐岩油藏高产带预测问题分解成构造解释、岩相预测、岩溶预测、物性预测、裂缝预测和综合评价等六个环节。宏观上,通过建立断裂、岩相、岩溶模式,定性预测储层分布有利区带;微观上,通过多参数储层特征反演和多属性综合分析,定量、半定量预测有利储层分布,有效解决盐下碳酸盐岩油藏高产带预测难题,基本搞清本区碳酸盐岩油藏高产带分布规律,为优选有利勘探和开发目标提供依据。文中提出的方法和技术对解决国内外碳酸盐岩油藏高产带预测和其他复杂储层预测问题有借鉴作用。  相似文献   

17.
In 2005, six major eruptions of four Kamchatka volcanoes (Bezymyannyi, Klyuchevskoy, Shiveluch, and Karymskii) occurred and the Avachinskii, Mutnovskii, and Gorelyi Kamchatka volcanoes and the Ebeko and Chikurachki volcanoes in northern Kurils were in a state of increased activity. Owing to a close collaboration between the KVERT project, Elizovo airport meteorological center, and volcanic ash advisory centers in Tokyo, Anchorage, and Washington (Tokyo, Anchorage, and Washington VAACs), all necessary measures for safe airplane flights near Kamchatka were taken and fatal accidents related to volcanic activity did not occur.  相似文献   

18.
利用地震前兆数据跟踪分析平台,搜集并梳理全国定点形变观测台SS-Y型伸缩仪2016—2018年数据跟踪分析观测系统事件记录、观测日志,按影响因素分类,归纳为前置放大器、传感器、主机、供电、传输线路、避雷器、标定装置等13种故障类型,分析各故障类型中发生的曲线特征与技术解决措施,为基层台站伸缩仪观测日常运维中快速锁定故障位置提供参考,进一步提高观测数据的完整性、连续性,提高数据跟踪分析工作的实际效能。  相似文献   

19.
Seawater intrusion (SI) is a global issue, exacerbated by increasing demands for freshwater in coastal zones and predisposed to the influences of rising sea levels and changing climates. This review presents the state of knowledge in SI research, compares classes of methods for assessing and managing SI, and suggests areas for future research. We subdivide SI research into categories relating to processes, measurement, prediction and management. Considerable research effort spanning more than 50 years has provided an extensive array of field, laboratory and computer-based techniques for SI investigation. Despite this, knowledge gaps exist in SI process understanding, in particular associated with transient SI processes and timeframes, and the characterization and prediction of freshwater–saltwater interfaces over regional scales and in highly heterogeneous and dynamic settings. Multidisciplinary research is warranted to evaluate interactions between SI and submarine groundwater discharge, ecosystem health and unsaturated zone processes. Recent advances in numerical simulation, calibration and optimization techniques require rigorous field-scale application to contemporary issues of climate change, sea-level rise, and socioeconomic and ecological factors that are inseparable elements of SI management. The number of well-characterized examples of SI is small, and this has impeded understanding of field-scale processes, such as those controlling mixing zones, saltwater upconing, heterogeneity effects and other factors. Current SI process understanding is based mainly on numerical simulation and laboratory sand-tank experimentation to unravel the combined effects of tides, surface water–groundwater interaction, heterogeneity, pumping and density contrasts. The research effort would benefit from intensive measurement campaigns to delineate accurately interfaces and their movement in response to real-world coastal aquifer stresses, encompassing a range of geological and hydrological settings.  相似文献   

20.
Chinese scientists proposed that large earthquakes that occurred in mainland China are controlled by the movement and deformation of active tectonic blocks. This scientific hypothesis explains zoned phenomenon of seismicity in space. The active tectonic blocks are intense active terranes formed in late Cenozoic and late Quaternary, and the tectonic activity of block boundaries is the intensest. Global Navigation Satellite System(GNSS)has advantages of high spatio-temporal resolution, broad coverage, and high accuracy, and is utilized to monitor contemporary crustal deformation. High accuracy and resolution of GNSS velocity field within mainland China and vicinities provided by previous studies clearly demonstrate that different active tectonic blocks behave as different patterns of movement and deformation, and block interaction boundaries have intense tectonic deformation. The paper firstly introduces the GPS networks operated by the Crustal Movement Observation Network of China(CMONOC)since 1999, and GNSS data processing methods, including GAMIT, BERNESE and GIPSY/OASIS, and discusses the advantages of using South China block as a regional reference frame for GNSS velocity field, then proposes three strategies of block division, F-test, quasi-accurate detection(QUAD), and clustering analysis. Furthermore, we introduce rigid and non-rigid block motions. Rigid block motion can be denoted by translation and rotation, while non-rigid block motion can be described by rigid motion and internal strain deformation. Internal strain deformation can be divided into uniform and linear strains. We also review the usage of F-test to distinguish whether the block acts as rigid deformation or not. In addition, combining with recent GNSS velocity results, we elaborate the characteristics of present movement of rigid block, such as the South China, Tarim, Ordos, Alashan, and Northeast China, and that of non-rigid block, such as the Tibetan plateau, Tian Shan, and North China plain. Especially, the Tibetan plateau and Tian Shan seem to deform continuously with significant internal deformation. In order to enrich and perfect the active tectonic block hypothesis, we should carefully design dense GNSS networks in inner blocks and block boundaries, optimize utilizing other space geodesy technologies such as InSAR, and strengthen combining study of geodesy, seismogeology and geophysics. Through systematic summary, this paper is very useful to employing GNSS to investigate characteristics of block movement and dynamics of large earthquakes happening in block interaction boundaries.  相似文献   

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